Belarus arrested the men last month, saying they had sought to destabilise the country prior to Sunday's presidential election.
Russia has announced the safe return of 32 of its citizens after Belarus detained them saying they were mercenaries sent to destabilise the country ahead of Sunday's presidential election.
Russia's Prosecutor-General's Office said in a statement that "32 Russian citizens who were earlier detained in Belarus crossed the border and are now in Russia."
It added that one other man, who has dual Belarusian citizenship, remained there.
The statement came after Belarus announced in late July ahead of August 9 presidential polls that it had detained 33 Russians at a health resort outside Minsk.
The Belarusian security service, the KGB, said they were fighters for the shadowy Wagner private army, reportedly funded by a close associate of Russian President Vladimir Putin.
Its recruits are believed to act in numerous foreign conflicts including in Syria and Ukraine.
Russia denies interference in polls
The Belarusian KGB initially said the men were sent to destabilise Belarus ahead of polls. A senior official said they were suspected of preparing a terrorist attack.
Belarus later changed its account, saying the men were facing a charge of making preparations for mass disorder, a criminal charge.
It suggested they acted along with detained Belarusian opponents of President Alexander Lukashenko including the husband of the main opposition candidate Svetlana Tikhanovskaya.
The men gave testimony that they were planning to travel on to foreign destinations including Venezuela.
It emerged that several of the detained men had fought alongside pro-Russian separatists in eastern Ukraine and Ukraine said it would seek to extradite them.
Russia has denied interference in the Belarusian polls but did not issue any harsh statements over the detentions while saying the men had done nothing wrong.
Lukashenko has close ties with Moscow although he has often sought to play Russia off against the European Union, and Moscow has publicly supported him during the latest protests.
The Belarusian strongman issued more conciliatory statements about the incident ahead of the men's release.
A Russian tabloid, Komsomolskaya Pravda, reported that the whole operation had been organised by Ukraine as a provocation.
Lukashenko has now shifted to blaming the protests on other foreign countries as thousands take to the streets in peaceful demonstrations against police violence and against the polls they said were rigged to re-elect the strongman.
On Friday he claimed people had arrived from Poland, Ukraine and the Netherlands to direct the protest movement.